A conventional slant plate compressor such as a wobble plate type compressor includes a compressor housing, a front end plate, and a cylinder head. A cylinder blck and a crank chamber are formed in the compressor housing. The front end plate is attached to one end surface of the compressor housing to cover the opening of the housing. The cylnder head is disposed on the other end surface of the compressor housing adjacent the cylinder block through a valve plate. A suction chamber and a discharge chamber are formed within the cylinder head. A plurality of cylinders are formed in the cylinder block and pistons are reciprocatingly placed with the cylinders. A drive shaft extends within the compressor housing, and is rotatably supported within an opening in the front end plate through a bearing. A drive mechanism for reciprocating the pistons is mounted on the drive shaft in the crank chamber. The drive mechanism includes a rotating portion and a mechanism for converting rotational motion into transitional motion. Each piston is coupled to the drive mechanism through a connecting rod.
In slant plate type compressors, both the wobble plate and the swash plate are disposed at a slant angle and drivingly couple the pistons to the drive source. However, the wobble plate nutates only. The swash plate both nutates and rotates. The term slant plate type compressor will be used to refer to any type of compressor, including wobble and swash plate types, which use a slanted plate or surface in the drive mechanism.
In a conventional refrigerant compressor, while the refrigerant gas is compressed by the reciprocating motion of the pistons, moving parts of the compressor must be lubricated by lubricating oil. One lubricting method for a wobble plate type compressor is disclosed in U. S. Pat. No. 3,712,759. In this compressor, refrigerant containing lubricating oil is directly introduced into the crank chamber from the external refrigeration circuit through an inlet port. A suction chamber and a discharge chamber are formed in the cylinder head; the suction chamber is located at the center of the cylinder head, and the discharge chamber is located around the suction chamber. A communication hole which communicates between the crank chamber and the suction chamber is formed within a central portion of the cylinder block. The refrigerant containing the lubricating oil directly enters the crank chamber and lubricates the moving parts of the compressor. Lubricating oil is spread on the inner wall surface of the crank chamber by the centrifugal force of a rotor and gradually accumulates in the bottom portion of the crank chamber.
However, this compressor does not have adequate lubricating oil circulation. Therefore, additional lubricating oil is needed to prevent inadequate lubrication of the moving parts of the compressor, and additional lubricating oil may be required. Moreover, if too much lubricating oil or the like exists in the refrigeration circuit, the refrigerating capacity of the refrigeration circuit decreases.